4. Materials and Methods 4.1. Plant Material, Growing Conditions, and Shade Treatments I. sinensis var. przewalskii is a perennial herb of Bignoniaceae that is distributed in southwestern, northwestern to northeastern China under mingled forest (2000–2600 m above sea level). The flowering and fruiting season may last for nearly 5 months, from early June to early November [1]. The terminal racemes generally have 5–15 flowers, which are pale yellow and campanulate-shaped.
